Take-off and landing simulating means for grounded aviation trainers



Oct. 18, 1949. R.- H. LEWIS TAKE-OFF AND LANDING SIMULATING MEANS FOR 3 Shee ts-Sheet 1 GROUNDED AVIATION TRAINERS Filed Nov. 7, 1947 MOM .On 00% tz: 32m 1 E new we men 4m 25 A T TOE/VF Y Oct. 18, 1949. R. H. LEWIS TAKE-OFF AND LANDING SIMULATING MEANS FOR GROUNDED AVIATION TRAINERS 3 Sheets-Sheet 2 Filed Nov. 7, 1947 m w L m H DN /4 E 0V M m M R I Y B 8 MY 2 s 3 J c Q 0 5 4 .O 3 7|. Q 3 I k o 4 m 2 3 M m 8 3 6 7 m n F a ATTORNEY R. H. LEWIS TAKE -OFF AND LANDING SIMULATING Oct. 18, 1949.

- MEANS FOR GROUNDED AVIATION TRAINERS 3 Sheets-Sheet 3 Filed Nov. 7, 1947 ALTITUDE RAYMOND H. LEWIS 430 NVENTOR FIG. 8

ATTORNEY Patented Oct. 18, 1949 TAKE-OFF AND LANDING SIMULATING MEANS FOR GROUNDED AVIATION TRAINERS Raymond H. Lewis, Binghamton, N. Y., assignor to Link Aviation, Inc., Binghamton, N. Y., a corporation of New York Application November 7, 1947, Serial No. 784,616

8 Claims.

This invention relates to grounded aviation trainers, and more particularly to means for simulating the take-off and landing of airplanes by such trainers.

In the case of an airplane, during the initial phase of its take-off run, i. e., until a certain air speed is reached, any movement of the controls of the plane and resulting movement of the control surfaces will not substantially affect the climbing, diving or banking position of the plane. However, when the critical air speed is reached, 6. g., 25 knots, the relative motion between the elevators of the plane and the air through which the plane is traveling, even though the plane is still on the ground, is sufiicient that when the pilot presses the control column ahead the coaction between the elevators of the plane and the air is sufficient that the nose of the plane will be lowered and the tail of the plane will be raised from the ground. However, at the air speed being considered it still is not possible to substantially bank the plane. Return of the control column to its neutral position results in a lowering of the tail of the plane.

As the air speed of the plane increases and another critical air speed is reached, e. g., 75 knots, the coaction of the lift surfaces of the plane with the air through which the plane is moving is such that the plane has enough lift to become airborne, and the plane leav'es the ground. Having left the ground, the plane'can of course be moved about any of its three axes by the pilots operation of the controls of the plane.

When the plane later returns to the ground, the pilot is able to keep the tail of the plane off the ground until the air speed has been reduced to a certain amount, e. g., 25 knots, but the pilot is not able to cause the plane to bank. When air speed has been reduced to 25 knots, the tail of the plane drops to the ground, and any diving, climbing, or banking of the plane is impossible.

This invention relates to means for simulating the aforedescribed landing and take-off characteristics of a real plane, and will be described in conjunction with a trainer of the type including a fuselage universally mounted upon a stationary base for pitching and. banking in response to movements of the controls within the fuselage which simulate the pitch and bank controls of a real plane, to simulatethe pitching and banking of a real plane in response to the movements of its controls. Such trainers are well known to the prior art, and for a disclosure of one such type of trainer reference may be made to United States Patent 1,825,462 dated September 29-, 1931, and

v bellows l8.

issued to EdwinA. Link, Jr., for Combination training device for student aviators and entertainment apparatus.

In order that the preferred embodiment of my invention may be thoroughl understood, reference is made to the accompanying drawings wherein,

Fig. 1 is an exterior side view of a trainer of the type with which my invention will be illustrated.

Fig. 2 is a general schematic view of the essential parts of my invention.

Fig. 2A is a schematic View of the nose down solenoid control arrangement.

Fig. 3 is a detailed view, partly in cross section, of a double acting spring compensator assembly which is used in conjunction with the form of my invention disclosed herein.

Fig. 4 is an exploded perspective view of the bank leveling valve which forms an important part of my invention.

Fig. 5 is an exploded perspective view of the switching valve and control motor which form an important part of my invention.

Fig. 6 is an exploded perspective View of the nose-down control valve which forms a part of my invention.

Fig. 7 is a perspective view of the nose-down control bellows and associated apparatus.

Fig. 8 is a diagram of the electrical circuit which controls the motor shown in Fig. 5.

Reference is now made to Figs. 1 and 2 wherein there is disclosed the well known rotatable platform in which carries the forward pitching or dive bellows H, the rear pitching or climb bellows Hi, the left banking bellows l6 and the right banking The rotatable platform It] is supported by the vertical spindle 20 which is suitably rotatably mounted in the stationary base 22. Above the rotatable platform I0 and the four mentioned bellows is carried the fuselage 24, the bottom of which is designated 26 and to which the upper edge of each of the four bellows is connected by members 21. Mounted upon the top of vertical spindle 20 is the universal joint 28 which supports the fuselage 24 to permit pitching and banking movements of the fuselage to simulate the climbing, diving and banking of a plane in actual flight.

Reference is now made to Fig. 2 where the conventional aileron Valve is designated generally by 30, this valve comprising the lower fixed portion 32 which is mounted upon the main vacuum manifold 34 which is affixed to the bottom 26 of fuselage 24 and the upper rotatable leaf 36 which carries the arm 31. This arm is connected by the washer I 4 bears against the right end of the schematically shown connection 37a to the control wheel 39 in the fuselage 24 so that when the student turns the control wheel 39 counterclockwise to produce a left banking of the fuselage the upper leaf 36 is rotated counterclockwise in Fig. 2, and when the student rotates the control wheel clockwise lea'f "36 is similarly rotated clockwise. The construction of the aileron valve 36 and the connection between this valve and the control wheel 39 is well known to the prior art, and consequently a detailed disclosure of the same is not deemed necessary in this application. It is suflicient to know that the lower fixed leaf 32 of the aileron valve 30 carries a port "38 which is connected through the pneumatic line 40 to the port 42 carried by the lower fixedleaf 44 of the main switching valve of this invntiiin which is designated generall by 46. The lower leaf 320i the aileron valve 30 also carries a second exterior port4'8 which is connected throughthepneumatic line 50 to the exterior port 52 of the lower fi-X'ed le'af '44 of valve 46. h

, The conventional elevator valve of trainers of thetype being considered is designated generally which 'iscarrie'd by the 'r'r'iai'nvacuum manifold '34 and the upper rotatableleat 58' which carries the arm 60 to the outerend of which is pivotally attached the forward end of link 62. The rear end of link '62 is pivotally attached to the upper end of lever '64 which is pivoted upon the fixed pivot 66, and therear end of another link 7 as 1 is 'piveteuy attached to the lower'end of lever'64. Link 681s eermeeted te the contrbl colu'mn'69 in the traine through the schematically shown coiir'ie'c'tion 69a to be responsive to foreand aft 'rrioveinehtsof the'control column 69 so that whenjhe control column is bashed ahead the link 68 reeve to the "rear, resulting in a counterclockwise rotation "of the lever 64 and ma forward movement oi link 62. The upper leaf "or the elevator valve 54 rotates clockwise. On theotli'e'r h'a'n'da i eerwerdmeveinent'of 'the control'ccluiiih results in'i'ndveinent er the j-usthientidfid partsih iippcsite'directions.

The lower fixed leaf 56 of theelevattirvalvefl carries th'ehxterior port lll fwhich is "connected through the pneumatic" line 12 to theiekterior "port 'T'4carried'by theupperfiiifedleaf "I6oftl'ieswitching valve 46. The lower leaf 56 er valve 58 "also carries a second e'xteridr port "I8 WhichfiS 'connected through the erieem' u'e *line '80 witnthe exterior pe'rt -82 carried by the upper "leaf I6 of valve 46. i if The [bank leveling valve of this invention is shownfin Fig. 2a-nd is designated generally b37 84, this valve 'includirig a lower fixed leaf a'e which is afiiked tothe -b(')tt'(')m"2"6of the trainrffuselage, aswell as an upperrotatable leaf 88 which carries the arm '68 to which'is aflixed one end-ofthe link 82"whic'h extendstransverselyhf the trainer-fusela'ge. The'oth'ere'ii'd of link 92 carries the double acting compensator assembly designatd generally by =94, a detailed' disclbsure of which is shown :in Fig. 3, to w hichrefernc'e isnowfrnade. -It'u rill ue eeen that the "assembly 94 includsa sleeve 96 which is afiiX'ed upon the link' 92 and around the fixed sleeve 96 is a movable sleeve 98' to "which is attachedthe'lower eiid of the bent link I 00. A

sleeves 96 'and j9'8,-a's seen-in Fi g. -3 ,and the left end of the compression spring Hi6 bears -against the washer 104. The right of spring -I06 bears against another washer 5 I08 which is pieced iipehimk a'ueiiu' the eette'r i-n Ilil passes throu gh 4 link 92 to limit the movement of washer I06 therealong.

The left ends of the sleeves 96 and 98 are engaged by the washer H2 which in turn bears against the right end of the second spring H4 which encircles the link 92, the left end of this spring I I4 being held in place by the washer H6 and cotter pin H8.

Referring back to Fig. 2, the upper end of bent link I00 is pivoted to the upper end of arm I02, the lower end of which is afiixed upon the horiz'ontal sha-f't I carried by the brackets I22 which are affixed to the bottom 26 of the trainer fuselage. Attached to the forward end of the horiream shaft "I20 is the inner end of arm I24, the outer end of which p-ivotally carries the upper end of the bent 126, the lower end of which is fixedly attached to the outer sleeve I28 of a spring compensator assembly designated generally by I30 and which i s carried by the upper end of the vertical l ink I32. I62 passes "through *the bottom 26 of the fuselage by means of a suitab'le clearance hole (riotsh'Own) and the lower rid er link I32 is pivotally attached to the bradhet I34 which is affixed to the platform I 0 to the left of the universal joint =28 and on -the transverse as I35 which is below the mix/cree joint. As-seen in Fig. 2, this 'axispasses th'r'c'iugh 'the 'e'enrers er the bank bellows I6 and P8. The spring coinpensating assembly designated generally by IE0 is constructed exactly like the assembly shown in detail in Fig. 3.

Reference is nowniade "to Fig. *1 fora detailed disclosure of the bank levelling valve desig'na't-e'd generally by84. "rheflower lee: etea'rriese central stem I36 which is 'connec'ted'to a suitable vacuum source I38 by means 'df the "pneumatic line I40. Theuppereiid of's'teml is is'o'f reduced diameter, as indi'c at'ed at mane he e plurality of perforations I44. The 'iippei' leaff88 includes a central chamber I46a d'a eezpjr ajtheemereea upper portion I 50 6f m ffittiii'g inside eat: me and the'p'or'tion of'si'ri'aller aieg'me't'e'r :42 being within chamber I46. The "clfaim'ber I46 is connected through the interior "duct I'SZtothe'port I54 in the lower face of lea-f 88. The upper'lea'f 88 also includes an atmosphere port 156 which is connected through the interior duct -[5'8 with the port I in the lower-face of leaf "8'8, and leaf 8 8 also has a second atmosphere port I62 which connects-by means of the interior duct I64 with the port I66 in the lower face cf-leaf 88. M

The lower-leaf 86 of the bank leveling va1ve'84 includes the port I68 intheupper face of the leaf, which port connects with theext erio r coupling I70 by-means' of theinterior duct H2. The upper face "of leaf 86 has the-second port -I I4 which-is connected through =the-interior duct 1-18 with the exterior coupling I16. Referring now to -2, it will :b seen tha-t'the' exterior coupling I10 is connected through the pneumatic line I with theexterior coupling I82of the lower leaf 44-015 switching valve 46. The exterior coupling I16 of valve 84 is connected through pneumatic-line 1'84 with'theexterior coupling 'I86 ofthe"leaf '44 of valve 46.

Referring back to l igflijt should be understood that whenthe upp er-1eaf-=88 is'in neutral rotatabre "position with 'iespe'ct to the lower -'-le'af 86, the vacuum I54 lies between the po'rts I68 and I1 4 in the lower leaf, the 'diai neter of port 1'54 being substantially e'qua1 to the'-dist'an 'cebetween the eaje'eem edges-of 1 ports #68 and '14. Under wise of port I68, while port I66 lies just counterclockwise of port "4.

Also shown in Fig. 2 is the pitch leveling valve designated generally by 84a. This valve is identical in construction with the bank leveling valve 84 which has been described in detail, and the upper rotatable leaf 88a of the pitch leveling valve 84a. is connected through a series of linkages, compensator springs, etc., to the rotatable platform I exactly like the corresponding series which interconnects the platform I0 and the valve 84. necting the leaf 88a of valve 84a with the base I0 are given the same numbers as the corresponding elements interconnecting the valve 84 and base I0, with the exception that the suffix a is added to the reference characters to distinguish the two systems. Consequently, a detailed description of the system interconnecting the valve 84a and the-base I0 is deemed unnecessary, but it should be pointed out that the bracket I34a is affixed to the platform I0 at a point to the rear of the universal joint 28 and on the longitudinal axis I35a which is below the universal joint and passes through the centers of the dive bellows I2 and climb bellows I4.

Inasmuch as the pitch leveling valve 84a is identical in construction with the bank leveling valve 84, a detailed description of the construction of valve 84a is deemed unnecessary. In Fig. 2, the shown parts of valve 84a are given the same numbers as the shown parts of the valve 84, with the exception that the sufiix a is added to the reference characters of valve 84a. The exterior port "M of valve 84a is connected through the pneumatic line I80a to the exterior port I820; of the upper fixed leaf 16 of the switching valve 46, while the exterior port II6a of valve 64a is connected through the pneumatic line I84a to the exterior port I86a of leaf I 6 of the switching valve 46.

Reference is now made to Fig. 5 which is an exploded view of the switching valve designated generally by 46. The previously mentioned parts of valve 46 are numbered in Fig. 5 according to the numbers previously assigned, and it will be seen that in addition to the lower fixed leaf 44 and the upper fixed leaf I6, the switching valve 46 also includes the rotatable middle leaf I90. The exterior coupling 52 of the lower leaf 44 is connected through the interior duct I92 to the port I94 in the upper face of the lower leaf; the exterior coupling I82 is connected through the interior duct I96 with the port I98 in the upper face of the lower leaf 44; the exterior coupling 42'is connected through the interior duct 200 with the port 202 in the upper face of leaf 44; and the exterior coupling I86 is connected through the interior duct 204 with the port 206 in the upper face of leaf 44. A first additional exterior coupling 208 is attached to the lower leaf 44 and is connected through the interior duct 2) with the port 2 I 4 in the upper surface of the lower leaf 44. As seen in Fig. 2, exterior coupling 208 is connected through the pneumatic line 2I6 with the right banking bellows I8. The second additional I exterior fitting 2I8 is carried by the lower leaf 44 of the switching valve 46, and this exterior coupling is connected through the interior duct 220 with the port 222 in the upper surface of leaf 44. Referring to Fig. 2, it will be seen that the exterior coupling 2I8 is connected through the pneumatic line 224 to the left banking bellows I6. Considering now the detailed construction of the upper leaf I6 of the switching valve 46, it

Accordingly, the elements interconwill be seen in'Fig. 5 that the exterior coupling I82a of leaf I6 is connected through the interior duct 226 with the port 228 in the lower face of leaf I6; that the exterior coupling I4 is connected through interior duct 230 with the port 232 in the lower face of leaf I6; that exterior coupling I86a is connected through interior duct 234 with the port 236 in the lower face of leaf I6; and that the exterior coupling 82 is connected through the interior duct 238 with the port 240 in the lower face of leaf I6. Leaf I6 also carries the first additional exterior coupling 242 which is connected through the interior duct 244 with the port 246 in the lower face of leaf I 6, and referring to Fig. 2 it will be seen that coupling 242 is connected through the pneumatic line 240 with the dive bellows I2. The upper leaf I6 also carries the second additional exterior coupling 250 which is connected through the interior duct 252 with the port 254 in the lower face of leaf I6. As seen in Fig. 2, exterior coupling 250 is connected by means of pneumatic line 256 with the climb bellows I4.

The lower fixed leaf 44 has a hollow center 260, the central rotatable leaf I90 has a hollow center 262, and the upper fixed leaf I6 has a hollow center 264. The central stem 266 fits in the hollow centers of each of the three leaves to concentrically position the same with respect to one another.

The central leaf I90 of the switching valve 46 has two diametrically opposed kidney-shaped counterbores 268 and 210 in the lower face of leaf I90, and has another pair of diametrically opposed kidney-shaped counterbores 212 and 214 in the upper face of the leaf.

In Fig. 5 it will be seen that the center leaf I90 of the switching valve 46 carries the extension 460 to which is pivotally attached one end of the link 402, the other end of which carries the spring compensating arrangement designated generally by 404 and which is constructed like the arrangement shown in Fig. 3. The outer sleeve of the spring compensating arrangement 404 is numbered 406 and is attached to the outer end of arm 408 which'in turn is fixed upon the vertical shaft 4I0 which is positioned by the motor 4I2. Also afiixed upon the shaft 4I0 are the cams M4 and M6 and upon which ride the rollers 4| 8 and 420 respectively carried by the movable arms 422 and 424 of the microswitches 426 and 428.

Reference is now also made to Fig. 8 which is an electrical wiring diagram of the circuit controlling the operation of the motor 4 I2. In Fig. 8 it will be seen that the relay 430 is provided, one side of this relay bein connected to one side of the volt source through the conductors 432 and 434 while the other side of this relay is connected through the conductor 436, fixed switch element 438, movable switch element 438a, conductor 440 andcond-uctor 442 to the other side of the 110 volt source. Switch element 438a is under the control of the cam 444 which is afiixed upon the shaft 446 positioned by the altitude unit 448 which is shown in block form. It is sufficient to know that the shaft 446 is always positioned according to the instant assumed altitude of the trainer, the cam 444 being positioned upon the shaft 446 and arranged relative to the movable switch element 438a to bring the same into engagement with the fixed switch element 438 to energize relay 430 at all times when the assumed altitude is above zero. The conductor 434 which connects with one side of the 110 volt sourceis attendee connected to the newbie switch element i150 white the ooniiuctorflli which connects with the other side the no volt soi-irce is connected to the movable switch eiement K52. A th' ird movable switch element 4% is shown and :is "conheated through the conductor I56 the right side (if the armature i Ma oi motor W2. Associated with the movable sw'iteh elemeiit432 are the hired contacts 432a and 4521;, the iormer contact being connected through the conductor $611 with the n'i'ioroswitch element $22 under the control of cam 41!, and the latter being connected through the conductor [62 with the movable nucroswitch element 52! which is controlled by ca'm 4 1 B. Fixed switch elements 450a and "4-507: are associated with the movable switch element I511, the foriner being connected through con-- duc'tor W64 with'ones'ide o'f the 'fiel'd winding #1 12b of motor H2, and the latter being connected through'tliecondutor46B with the other side of field Windlng i F2'b."'Ihe "fixedswitoh elem'eiit's454a and 15% are associated with the movable contact 454, the former being connected through the jumper iii-8 with the previously mentioned fixed switch element tact, and the latter being connected throu'gh the conductor "410 with conductor F64.

The fixed switch elements 426 and 428 are interconnected by the conductor 4-", and one end of conductor 412 is connected through "conductor ll l with theleft side (if the armature "412a of mot'o'r 4 f2.

"It has beenstatedthaftthe cam! closes switch elements 433, "43th at assumed altitudes above zero. The lementsare open at all other times. Relay 430 is energized 'whenever'switch elements 438, 438a are cl0s'ed,"and"the movableswitch elements 452, 450 and "45'4 are 'con'tfolled by irelay 30. The positions of the "three just mentioned movable switch elementswhen the'relay 43B isdeenergized ares'how'n inFig. 8. "The'c'am 41B and the cam 404 are arranged and the switches controlled 'thereby are of the "type that one of the switches c'ontrolled bythese cams is closed atal-l times and one of the switches controlled Joy the cams is open 'a't all times. will'become vmore clearly understood, the movable switch element 424 controlled by cam 41 6 is positioned Jay the cam to contact the fixed switch element-428 when assumed altitude iszabove zero, but when assumed altitude is zero or below, the movable -oontact *4 24 is disengaged from fixed contact 428. 0n the other-hand, cam ll l controls the movable-switch element 422 so that the movable switch element engages the fixed switch element 426 only when the trainer isatan assumed altitude of zero, and whenthe trainer is air-borne, the movable switch element 422 is displaced from the fixed switch element 426.

The detailed description of the operation of the electrical circuit 'of 8 will he later given, it being deemed sufiicient to state at this time that the unit'448 controls relay 43 2! to energize the motor M2 to .positionthe 'central leaf 190 of thesW-itohing valve 46 according to whether it is assumed the plane represented-by the trainer is airborn or grounded.

Thekidn-ey shaped counterbores 268 and 210 are-shaped and. positioned so that when the control rotatable leaf 4911 HS in its clockwise positiony as is the-case =when-the trainer is'assumed to -be grounded, the kidney shaped counterbore 288 in *the bottom of leaf I90 -=connects the port 406 in the top :face of bottom leaf '44 with the adjacent port 2W4, and port "I94 is discoi'mected from the port 2 l4. At the same time, the kidney shaped counterbore 2-11] in the bottomiaoe of leaf 1% connects "the port 198 with the sport 222, Thu-t port 232 is disconnected from part 2 22. Consequently, the banklevelin'g valve 84 is connected with the loan k bellows 1'6 and 18, but aileron or bank valve 3 0 is disconnected ifrom'the bank bellows l6 and M8.

The kidney shaped coun't'erbor'es M2 and 2 in "the upper face er the central ilea'f IQO are shaped and positioned so that when center leaf 19:] is in its clockwise position, the kidney:shap'ed counterbore 2T2 connects the port 2315 with the port 2 54 in the lower face of the upper fixed leaf 7 6, and port 240 is cut off from the 'port 254. At the same time the k idney shaped 'coun'terbore 2' in the upper face of the middle leaf I!!! con-- nec'ts the ports 2'28 and 246 in the lower "face of the upper leaf, but "port 232 in the same surface is cut off from "the port 244. Consequently, when the middle l'ea'f 49D is rotated into its clockwise position, as is the 'case when the trainer is assumed to begroundedythe main aileron "valve 3!! is disconnected from the "bank bellows 1'6 and it, the main elevator valve 54 ist'lisconnectedfrom' the dive and clinib bellows f2 and P4, the bank leveling valve til is connected to the "banking bellows it and "I8, "and the auxiliary pitch valve 8 5a isconn'ecte'd to the dive bellows l2 and climb bellows M.

It will be appreciated without a detailed explanation that when the central leaf ['90 is 1'0- tated into its counterclockwise position, as is the case 'whenthe trainer'is assumed to bean-borne, the kidney shaped 'c'ounterbores in the upper and lower surfaces of'th'e middle'leaf II willb'e moved out of .Tpo'sitions overlapping the'portsin the upper leaf T6 and lower lea'i 44 which connect with the auxiliary valves a l and 84a, andw'ill instead be moved into positions overlapping the ports which lead to the main aileron valve 30 and main .elevator valve 54, at the same time continuing to overlap the ports-which go to 'the'hellows l2, [4, l6 and T8. Consequently, when the middle leaf T90 is in the counterclockwise ,position, the auxiliary valves 84 and 84a will be disconnected from the main bellows, -but the conventional main aileron valve I31] and elevator valve '54 will-be connected to the four main bellows which control the attitudeof the fuselage .upon the universal joint.

Referr-ing again -to-4Fig. 2A the airspeed .unit or the trainer is shown in block iform and-designated by 30D. The-output shaft 30] .of the air speed unit one is ,positioned "according to the instant assumed air speed and cam -302 which is aflixed .upon shaft -30l is arranged to close the switch 303 -to energize .the solenoid when the -..assumed :air speed -is :the predetermined amount, -e. ex, 25 knots, or higher, and to :open the switch when :the assumed :air speed -is lower than :the predeterminediamount. The-plunger of the solenoid tilt as seen in-Fig. =2,.is .numbered iillfi. This plunger is pivotally connected to the ram 388 integral with-the upper leaf \3-l0ioi the-n0se-down control valve 4H2, which valve calso comprises a lower fixed leaf '3 I 4. Reference :is now made to Fig. 6 which is ran explodedview-of the valve-3152. The lower leaf iii-moi this valve is suitably aifixed *to'thebottom 26 of the trainer fuselage and this valve includes 'the port 316 i in the upper .face :of the lower leaf which =connects with the exterior fitting l 8, as -wellias port :320 beside itheiport :316, :port 320 =being connected to the-exterion-fite ting 322. The upper leaf 3I0 includes a counterbore 324 in the lower face of the upper leaf, the upper leaf being hollow at the center 326 for the reception of the central stem 328. The lower leaf 3I4 is also hollow at 338 to receive this central stem. The exterior coupling 3I8 is connected by means of pneumatic line 332 with the nose-down control bellows shown in Fig. 2 and designated generally by 334. The exterior coupling 322 is connected through the pneumatic line 336 with the turbine I38 which provides a source of reduced air pressure. The lower leaf 3I4 carries the vertical stud 340 while the upper leaf 3I0 carries the two horizontal studs 338a and 388?) which coact with the vertical stud 348 to limit the rotation of the upper leaf 3I0. The spring 34011 has one end connected to the horizontal stud 338a and the other end to the member 3481) which may be suitably aflixed within the trainer fuselage. When solenoid 304 is energized, the'upper leaf 3I0 is rotated counterclockwise until stop 338D engages stop 340, and when the solenoid 304 is de-energized the spring 340a rotates the upper leaf 3I0 clockwise until stop 338a engages stop 340.

I Reference is now made to Fig. '7 where the nose-down control bellows 334 is shown. This bellows includes a fixed side 339 which is mounted upon the two brackets 3400 which in turn are pinned upon the vertical shaft MI by means of set screws 342. The bellows 334 also includes the movable side 344 having one end pivoted to the fixed side 339 and the usual fabric covering 346 which renders this bellows air-tight. Affixed to the movable side 344 is the bracket 348 to which the right end of link 350 is connected by means of pivot 352. -The left end of link 350 is carried 'by pivot 354 which in turn is carried by the outer end of the arm 356 which together with the hub 358 and arm 360 forms a bellcrank, this bellcrank being freely mounted upon the vertical shaft 34I. Pivotally connected to the outer end of arm 360 is the forward end of link 362, the rear end of which, as also shown in Fig. 2, is pivotally connected by means of pivot 364 to the slider 366 which is mounted upon the link 92a. Link 92a also carries the collar 368 which is aflixed upon the link 9211 somewhat to the rear of slider 366.

It will be seen that the arm 310 is aflixed upon the vertical shaft 34I by means of set screw 342, the outer end of arm 310 being connected to the previously mentioned link 68 by means of pivot 314.

link 68 is connected to the lower end of lever 64, which lever is connected to the upper leaf 58 of the elevator valve 54 by the intermediate link 62.

Referring now to Fig. 1 only, it will be seen that there is affixed to the lower platform In the stud 40I upon which the locking arm 403 is pivotally mounted. A stud 405 is carried by the bottom 26 'of the fuselage, this stud being arranged to proturned on to energize the turbine I38 and the sill The forward end of link 68, it will be re called, is connected to the control column 69 by means of connection 69a, and the rear end ofinstructor then disengages the locking straps 402, thus leaving the position of the fuselage 24 on the universal joint 28 to be controlled by the four main bellows I2, I4, I6 and I8. As the student starts his simulated take-off run, the assumed air speed will of course ,be below the amount required for the pilot flying the plane represented by the trainer to raise the tail of the plane off the ground, and also the air speed will be insufficient for the pilot to bank the plane. This phase of the take-off run is hereinafter referred to as the initial phase. Accordingly, the air speed unit 300 is arranged so that during the initial phase of the take-off run the solenoid 304 is de-energized resulting in a forward positioning of the plunger 306 under the control of spring 340a and in the positioning of the upper leaf 3I0 of the valve 3I2 in its clockwise position, The kidney shaped counterbore 324 in the bottom face of the upper leaf 3| 0 of valve 3I2 is positioned clockwise of the ports 3I6 and 328 in the upper face of the lower leaf 3I4. Consequently, the port 3I6 is not connected with the port 320, and therefore vacuum sition, moving the link 362 and the slider 366 into its foremost position. Consequently, when the student in the trainer moves the control column 68 ahead or to the rear, the resulting fore and aft movement of the link 68 results in a movement of the arm 318 and of the vertical shaft 34I upon which arm 310 is affixed. Inasmuch as the bellows 334 is also fixed to shaft 34I, this bellows will move with the shaft MI, and by means of link 358', bellcrank arm 356, hub 358 and bellcrank arm 360, the link 362 will be moved fore and aft by fore and aft movements of the control column 69 and of the link 68. However, the fore and aft movements of link 362 merely result in a sliding of slider 366 along the link 92a, and

:, slider 366 does not engage the collar 368 which is afixed upon link 92a. Consequently, the upper leaf 88a of the pitch level valve 84a is not affected by fore and aft movements of the control column 69 during the initial phase of the take-off run.

Also, during the initial phase of the take-off run, inasmuch as the assumed air speed will be below the amount required to make the plane represented by the trainer become air-borne, the central leaf I90 of the switching valve 46 will be positioned in its clockwise position, in which case the vacuum lines I80 and I84 connected to the bank leveling valve 84 will be connected to the vacuum lines 224 and 2 I 6 respectively, which lines run to the left banking bellows I6 and right banking bellows I8, respectively. At the same time, the vacuum lines 40 and 50 which connect the main aileron valve 38to the lower leaf 44 of the switching valve 46 will not be connected to the vacuum lines 2I6 and 224 which run to the banking bellows I6 and I8. Consequently, the main aileron valve 30 is disconnected from the banking bellows I6 and I8, and any movement of the upper leaf 36 of the aileron valve in response to movements of the control wheel 39 do not produce any operation of the banking bellows I6 and I8. However, inasmuch as the bank leveling valve 84 is connected through the described vacuum lines and switching valve 46 to the banking bellows I6 and IB, it will be appreciated that the bank leveling valve 84 is effective 1 l tocon-trol the lateral position of the trainer fuselage.

However, assuming that at any time during the initial phase of the simulated take-off run the fuselage 24 is displaced from the level horizontal position in that one side of the fuselage, e. g., the left side, becomessomewhatlower than the other, inasmuch as bracket I34 seen in Fig. 2 is affixed upon the horizontal platform Ill and the brackets I22 arecarried by the bottom 26 of fuselage 24, when the left side of the fuselage becomes lower than the right, the intermediate connecting link F32 will cause the arm I24 to rotate clockwise as seen in Fig. 2, and the shaft I20 and arm I02 be rotated the same direction. By means of link I 86 and the compensating spring arrangement 64, link 92 will be moved to the right in Fig. 2, resulting in a counterclockwise rotation of the upper leaf 88 of the bank leveling valve 84. Referring to Fig. 4, itwill be appreciated that when the upper leaf 88' is rotated counterclockwise of its neutral position in response to the lowering of the left side of fuselage 24, the vacuum port (54 which is normally positioned between the ports I68 and H4 in the lower leaf 86 will be moved into an overlapping position with respect to the port I14 and will apply vacuum to the pneumatic line I84. At thesame time, the atmosphere port I60 inthe upper leaf 88 which normally liesjust clockwise of the port I68 will also be placed into an overlapping position with the port I68, and atmosphere will be applied to the pneumatic line I88. Inasmuch as the central leaf F90 of the switching valve 46 i positioned in its clockwise position, the vacuum applied to line F84 is applied through the switching valve 46 to the pneumatic line 2 l 6 which runs to the right banking bellows I8, and this bellows is collapsed. At the same time, the atmosphere applied to the pneumatic line I80 is applied through the sWitching valve 46 to the vacuum line 224 which runs to the left banking bellows I6,,and that bellows is expanded. The collapsing of the right banking bellows I8 and the expanding of the left banking bellows It will result in a raising of the left side of the fuselage. Consequently, during the initial phase of the simulated take-off run the apparatus of this invention is arranged so that a lowering of the left side of the fuselage automatically causes the apparatus to function to produce a raising of the left side of the fuselage.

It will be appreciated without a detailed explanation that if during the initial phase of the take-off run the right side of the fuselage should become positioned below the level position, the apparatus interconnecting the upper leaf 88 of the bank leveling valve 84 with the bracket I34 which is affixed to the platform It will be operated to rotate the upper leaf 88 of the bank leveling valve 84 clockwise of its neutral position. Referring to Fig. 4, a clockwise rotation of the upper leaf 88 will result in the application of vacuum to the pneumatic line I80 which is connected to the left banking bellows I6 through the switching valve 46, and in an application of atmosphere to the pneumatic line I84 which is connected to the right banking bellows I8 through the switching valve 46. Accordingly, the left banking bellows I6 will be collapsed and the right banking bellows I8 will be expanded, and the right side of the fuselage will be raised.

It will therefore be appreciated that the apparatus of this invention is arranged so that during the initial phase of the take-off run, any displacement of the trainer fuselage 24 from the level horizontal position will result in an operation of the bank leveling valve 86 and in a resulting operation of the bellows I6 and I8: to: return the fuselage to the level transverse position. The apparatus of this: invention for accomplishing the preceding described result will maintain the fuselage 2t in the level transverse position with great accuracy and sensitivity. (Also, during the initial phase of the take-off run, the main aileron valve 30 and main, elevator valve 54 are disconnected from the bellows I 2, I4, I6 and I8 so that the student in the trainer cannot produce banking and pitching movements of the fuselage. These: conditions accurately simulate the. performance of a real plane during the initial phase of the take-off where the pilot cannot cause the plane to pitch or bank.)

Also, during the initial phase of the simulated take-01f run, the clockwise position of the center leaf I96 of the switching valve 46 disconnects the vacuum line 88 which runs from the main elevator valve 54 to the upper leaf I6 of the switching valve from the vacuum line 256 which runs from the switching valve upper leaf to the climb bellows I4, and also the position of the central. leaf I98 disconnects the vacuum line I2 which runs from the main elevator valve 54 to the upper leaf I6 of the switching valve 46 from the vacuum line 248 which runs from the same upper leaf to the dive bellows I2. Accordingly, any movement of the upper leaf 58 of the main elevator valve in response to a fore and aft movement of the control column 69 will not produce any operation of the dive bellows I2 and climb bellows I4, and consequently the control column 69 is rendered ineffective to control the pitch attitude of the fuselage 24.

At the same time, the clockwise position of the central leaf I96 of the switching valve 46 connects the vacuum line I84a from the pitch leveling valve 840. with the vacuum line 256 which runs to the climb bellows I4, and also connects the vacuum line IBIla which runs from the valve 84a to the upper leaf I6 of the switching valve 46 with the pneumatic line 248 which connects with the dive bellows I2. Consequently, the pitch level,- ing valve 84a is rendered operative to control the bellows I2 and I4 to affect the pitch attitude of the fuselage 24.

Assuming that during the initial phase of the simulated take-off run the pitch attitude of the fuselage 24 departs from the normal preselected position of the fuselage 24 about its transverse axis for the said initial phase, as by a lowering of the front end of the fuselage 24 below the position in question, by virtue of the fact that bracket I340, is affixed to the platform I0 behind the position of the universal joint 28, and that the brackets I22a are carried by the base 26 which is mounted upon the universal joint, when the nose of the fuselage 24 is lowered the arm I24a, shaft I28a and arm Ill2a, in Fig. 2 will all be rotated counterclockwise, and the link 92a will move ahead, resulting in a counterclockwise rotation of the upper leaf 88a of the pitch leveling valve 84a. Referring to Fig. 4 which shows the construction of the pitch leveling valve 84a (albeit the reference characters used in Fig. 4 are those of the bank leveling valve 84), when the upper leaf 88a is rotated counterclockwise in response to the lowering of the nose of fuselage 24, the vacuum port of the upper leaf will apply vacuum to the pneumatic line I84a which connects with the upper leaf E6 of the switching Valve and through the switching valve to the vacuum line 256 which will result in a raising of the nose of fuselage 24.

Consequently, the lowering of the nose of fuselage 24 immediately operates the apparatus of this invention to produce a raising of the nose of the fuselage.

On the other hand, should the rear of the fuselage 23 become displaced downwardly from its normal position during the initial phase of the simulated take-01f run, it will be appreciated that the apparatus interconnecting the bracket [34a and the upper leaf 88d of the pitch leveling valve 84a will produce a clockwise rotation of the upper leaf 88a, and vacuum will be applied to the pneumatic line [86a which is connected through the switching valve 46 and pneumatic line 248 with the dive bellows I2, while atmosphere will be applied to the pneumatic line I84a which is connected through the switching valve and pneumatic line 256 with the climb bellows I4. The dive bellows l2 will be contracted and the climb bellows l4 expanded, and the rear of the fuselage will be raised. Accordingly, the lowering of the rear of the fuselage results in an application of vacuum to the dive bellows l2 and of atmosphere to the climb bellows I4, and the rear of the fuselage is raised.

Consequently, during the initial phase of the take-off run, the apparatus .of this invention operates to maintain the fuselage 24 at the desired pitch attitude for the early phase of the take-off run, and the apparatus of this invention maintains the fore and aft position of the fuselage 24 in the desired position within a very small tolerance. It will be appreciated that the fore and aft position of the fuselage during the initial phase of the take-off run may be selected as truly level, or any arbitrary position of the fuselage 24 may be selected. For example, it may be desired to tilt the longitudinal axis of the fusepressing forward of the control column, the apparatus of this invention maintains the fuselage horizontally level and longitudinally stable at the desired angle, which angle may or may not be horizontal. Any movement of the control column or wheel to produce a change in the pitch attitude of the fuselage or in the banking position of the fuselage is without effect.

The preceding described conditions prevail until the second phase of the take-off run is reached,

"i. e., when the assumed air speed of the trainer reaches the predetermined amount required to enable the pilot to raise the tail of the plane represented by the trainer from the ground by press ing forward of the control column. When that predetermined amount, e. g., 25 knots, is reached, the apparatus of Fig. 2A energizes the solenoid 364 and the plunger 306 is moved to the rear,

i to

rotating the upper leaf 3l0 of the valve 3| 2 counter-clockwise and, referring to Fig. 6, it will be seen that the kidney shaped counterbore 324 in the lower surface of the upper leaf 310 will connect the ports 3I6 and 326 in the upper face of the lower leaf 3I4. Such being the case, the

vacuum line 336 which connects with the turbine I36 will be connected to the vacuum line 332 which runs to the bellows 334, and this bellows will be collapsed by the application of vacuum to its interior. The collapsing of the bellows 334 results in a movement ahead of the link 350 and in a clockwise rotation of the bellcrank arms 356 and 36:3 as seen from above, and in a rearward positioning of the link 362, the forward end of which is pivotally attached to the outer end of .arm 366. Consequently, the slider 366 is moved to the rear, the apparatus being adjusted so that when the control column 69 is in its neutral fore and aft position, and the bellows 334 is collapsed, link 362 is positioned so that the rear end of sleeve 666 just engages the forward edge of the collar 368 which is affixed upon the link 92a.

Consequently, upon the reaching of an assumed bellows 334, link 3511, and the bellcrank arms 356 and 360, and the link 362 similarly moves to the rear. As best seen in Fig. 2, the rearward movement of link 362 results in a rearward movement of the slider 366 upon the link 92a, and this slider engages the fixed collar 368 to move the entire link 92a to the rear. The upper leaf 88a of the pitch leveling valve 84a will be rotated clockwise, applying vacuum to the pneumatic line l86a and. atmosphere to the pneumatic line 184a. Through the upper leaf 16 of the switching valve 46, the vacuum applied to pneumatic line a will be applied to the pneumatic line 248 leading to the dive bellows l2, while the atmosphere applied to the pneumatic line l84a will be applied to the pneumatic line 256 leading to the climb bellows I4. The application of vacuum to the dive bellows I2 and of atmosphere to the climb bellows M will result in a lowering of the nose of fuselage 24 and in a raising of the tail of the fuselage, thus simulating the raising of the tail of the plane represented by the trainer from the ground. It will be appreciated that the rearward movement of link 92a is permitted by virtue of the provision of the spring compensating arrangement 94a.

Having lowered the nose of the fuselage 24, should the student release the pressure applied to the control column 69, the well known mechanical centering arrangement incorporated in trainers of the type being considered returns the control column 69 to the neutral position, resulting in a returning of the arm 316 and the mechanism interconnecting that arm and the slider 366 to their neutral positions. The spring compensating arrangement 9411 will return the link 92a and the upper leaf 88a of the pitch leveling valve 840, to their neutral positions, and the previously described functioning of the pitch leveling valve 84a to keep the fuselage 24 in the predetermined pitch attitude will again take place.

It will be noted that when the predetermined assumed air speed is reached which will permit the student to ra se the tail of the fuselage the student is not able to raise the nose of the fuselage because any rearward movement of the control column 69 will merely result in a movement of the slider 366 ahead along link 92c, and the main elevator valve 58 is cut off from the climb. and dive bellows I2 and I4 by the position of thecenter leaf I90 of valve 46. Also, any ro-- tation ofthe control wheel 39. to produce a banking of the fuselage 24 will be ineffective, because the, position of the middle leaf I90 of the switching valve 46 cuts off the main aileron valve 33] from the banking bellows I6 and I8.

Consequently, during the second phase of the simulated take-off run, the student in the trainer may by pressing the control column 69 ahead lower the nose of the trainer fuselage and raise the rear end thereof to simulate the raising of the tail of the plane represented by the fuselage from the ground when the required air speed is reached. However, the, student cannot raise the nose of the fuselage, nor can he produce a bankins. thereof.

The just; described conditions of operation con-- tinue until such time as, the assumed air speed reaches the predetermined amount required to render the airplane represented by the trainer air-borne, and a positive assumed altitude is obtained, as previously explained. At that moment, as seen in Fig. 8, the cam 444 moves the movable switch contact 438 into engagement with the fixed contact 43811 and relay 43% becomes energized, resulting in a movement of the movable switch elements 452, 450, and 454 to the right in Fig. 8, into positions engaging the fixed elements 452a, 450a, and 454a. respectively. The

electrical circuit comprising the conductor 434, movable switch element 450, fixed element 456a, conductor 464, field coil 4I2b, conductor 466, jumper 468, fixed switch element 454a, movable switch element 454, conductor 45%, armature 4I-2a, conductor 414, conductor 4T2, fixed switch element 426, movable switch element 422, conductor 460, fixed contact 4520., movable contact 452 and conductor 442 will-be completed. (Movable contact 424 will be displaced from fixed contact 428 because as previously stated, cam 4J6 engages elements 424, 428 only when the trainer isassumed to be air-borne.) Consequently, the motor H2 is energized to rotate its output shaft M0 to move the arm 408 and connecting link 402 so that the center leaf I90 of the switching valve 46 is rotated counterclockwise. This energization of motor 4 I2 continues until the center leaf I 90 has been rotated into its counterclockwise position, at which instant the cam M4 is positioned to displace the movable switch contact 422 from the fixed switch element 426, and motor 4I2 stops. At the same instant, cam 4.1.6 moves the movable switch element 424 into engagement with the fixed switch contact 428.

The moving of the Center leaf I60 of the switching valve 46 into its counterclockwise position, as previously explained, breaks the pneue matic connection between the bank leveling valve 84 and the bank bellows I6 and I6, and breaks the pneumatic connection between the pitch leveling valve 84a and the dive and climb bellows I2 and I4. Consequently, the bank levelin valve 84 and pitch leveling valve 84a are no longer effective to maintain the fuselage 2 4 in the predetermined take-off position. The counterclockwise positioning of the center leaf I96 of the switching valve 46 establishes pneumatic co motion e w en the neumat c, lines c eaecthi h he a a r n valve 32 and mai l vator valve 5 with th pneumatic i s w ich 9h nest the swi ch ng; val e w h he. our ma n bellows I2, I4, I6 and I8, Consequently, the main ai eron va ve 31 and main l vatoralve 54 are rendered effective tocontrol the pitch and banking position of the fuselage 24;, undo); the control of the control wheel 39 and control col; um 63.. Consequently, the student regulates the p ch and ba n p s i n. o th f se a e Z 2 a man pu ti c the control. wheel 33 nd can: r l ee um 69 n the ame manner that mi le controls the pitch and banking position oi a plane in actual flight.

The. simulated air-borne condition just men tioned prevails until the assumed altitude again reaches zero orground level, at which time the landing gear of the plane represented by the trainer will be assumed to touch the ground. When this condition is reached, the earn 444, seen in Fig. 8 is positioned by the altitude unit 448 to displace the movable switch contact 438m, from the fixed contact 438;, and relay 430 becomes, deenergized, resulting in a movement of the movable switch contacts 452, 450, and 454 into the positions shown in Fig. 8. Current then fl ws from conductor 434 to the movable contact 450 and then along the fixed contact 45017 to conductor 466 and through the field winding M2]; to the conductor 464, then along conductgr 41.0 to the fixed contact 4541) to the. contact 454, thence along conductor 456 through the armature M211 and by means of conductor 414 to the fixed contact 428. From contact 428 the circuit is completed along the movable contact 424 to the conductor 462 and fixed contact 4521), and by-means of movable contact 452 and conductor 442; back to the other side of the 110 volt source. It will be noted that in this instance current flows in the opposite direction through the field winding 4 I 2b and in the same direction through the armature 4 I 2a from the previously cited instance when the simulated take-01f took place. Consequently, the motor4I2 is energized to rotate its output shaft M0 in the opposite direction from the previously described instance, and the center leaf I of the switching valve 46 is rotated from its counterclockwise position to its clockwise position. When the clockwise position of this leaf is reached, the cam 4I6 displaces the movable switch element 424 from the fixed contact 428, and motor 4I2 stops. At the same instant, cam 4M places the movable switch element M8 in contact with the fixed contact 426.

The return of the center leaf I90 to its clockwise position renders the main aileron valve 30 and main elevator valve 54 ineffective to control the banking and pitching attitude of the fuselage 24, but reconnects the bank leveling valve 64, and pitch leveling valve 84a with the main bellows I2, I4, I6 and I8. Consequently, the functioning of the bank leveling valve 84 is reestablished, and the fuselage 24 is kept transversely level, while the functioning of the pitch leveling valve 34a is re-established to keep the longitudinal position of the fuselage 24 in the predetermined take-off position, modified only by the fact that the student in the trainer can lower the nose of the fuselage 24 by pressing the control column 69 ahead until such time as the assumed air speed drops below the predetermined amount, e. g., 25 knots, because the bellows 334 continues to be collapsed until the assumed air speed drops to that predetermined amount.

When assumed air speed drops to 25 knots, the predetermined amount, the arrangement shown in Fig. 2A opens the switch 303 and the solenoid 304 becomes deenergized. Spring 340a of Fig. 6 rotates the upper leaf 3ID of valve 3H2 clockwise, and the counterbore 324 is moved clockwise ofthe ports 316 and 320, and the supply of vacuum in port 320 is disconnected from port 3%. Bellows 334 expands, displacing the slider 366 from the collar 1568 upon the link 92a so that a forward movement of the control column 69 no longer causes slider 366 to engage the collar 368 to operate the upper leaf 88a of the pitch leveling valve.

Consequently, when the assumed air speed drops to the predeterminedv amount of 25 knots, the fore and aft movement of the control column 69 and. the rotation of the control wheel. 39 is ineffective to control the pitch and banking of the fuselage 24. This condition prevails until the assumed air speed drops to zero, at which. time it is assumed that the plane represented by the trainer is at a stop.

In view of the preceding. disclosure of the preferred. embodiment of my invention, it will be appreciated that this invention provides means for simulating, in conjunction with. a trainer having a fuselage mounted for pitching and banking movements, the various degrees of maneuverability of a. plane during. the various phases of its take-off run and air-borne flight, as set forth in detail hereinbefore. It will be appreciated by those skilled in the art. that many changes may be made from the disclosed embodiment of my invention without departing from the substance thereof. All such changes are intended to be covered, by the following claims.

I claim: 1. The combination of a grounded. aviation trainer comprising a fuselage universally mounted with respect to a stationary base, manually operable means in the fuselage simulating the pitching and banking control means of a real plane, motive means for changing the pitching andv banking position of said fuselage and a first control means connected to said manually operable means and to said motive means for actuating said motive means under predetermined conditions to universally pitch and bank said fuselage in response to movements of said manually operable means, a second control means connected to said manually operable means and to said motive means for actuating said motive means under different predetermined conditions to raise one end of said fuselage in response to movements of said manually operable means, an altitude unit and an air speed unit forming a part of the trainer and respectively operable in response to changes in the assumed altitude and assumed air speed of said trainer, means inter connecting said air speed unit and said second control means for rendering said manually operable means operable to raise one end of the fuselage upon the reaching of a predetermined assumed air speed, and means interconnecting said altitude unit and said first control means for rendering said manually operable means operable to universally pitch and bank said fuselage upon the reaching of a predetermined assumed altitude.

2.. The combination of a grounded aviationtrainer comprising a fuselage universally mounted with respect to a stationary base, manually operable means in the fuselage simulating the pitching and banking controlv means of a real plane, motive means for changing the pitching and banking position of said fuselage and a first control means connected to said manually operable means and to said motive means for actuating. said motive means under predetermined conditions to universally pitch and bank said fuselage in response to movements of said manually operable means, a second control means connected to said. manually operable means and to said motive means for actuating said motive means under different predetermined conditions to raise one end of said fuselage in response to movements of said manually operable means, an altitude unit and an air speed unit forming a part of the trainer and respectively operable in response: to changes in the assumed altitude and assumed air speed of said trainer, means interconnecting. said air speed. unit and said second control means for rendering said manually operable means operable to raise one end of the fuselage upon the reaching of a predetermined assumed air speed, means interconnecting said altitude unit and said first control means for rendering saidmanually operable means operable to universally pitch and bank said fuselage upon the reaching of a predetermined assumed altitude, and means forming. a part of said trainer for maintaining said fuselage in the level transverse position until both said predetermined assumed air speed and. altitude are reached.

3. The combination of a grounded aviation trainer comprising a. fuselage universally mounted with respect to a stationary base, manually operable means in the fuselage simulating the pitching and banking control means of a real plane, motive means for changing the pitching and banking position of. said fuselage and a first control means connected to said manually operable means and tosaid motive means for actuating said motive means under predetermined conditions to universally pitchand bank said fuselage in response to movements of said manually operable means, a second control means connected to said manually operable means and to said motive means for actuating said motive means under different predetermined conditions to raise one end of said fuselage in response to movements of said manually operable means, an altitude unit and an air speed unit forming a part of the 'trainer and respectively operable in response to changes in the assumed altitude and assumed air speed of said trainer, means interconnecting said air speed unit and said second control means for rendering said manually operable means operable to raise one end of the fuselage upon the reaching of a predetermined. assumed air speed, means interconnecting said altitude unit and said first control means for rendering said manually operable means operable to universally pitch and "bank said fuselage upon the reaching of a predetermined assumed altitude, means forming a part of said trainer for maintaining said fuselage in the level transverse position until both said predetermined assumed air speed and altitude "-are reached, and means forming a part of said- 19 plane, pneumatically operated motive means for changing the pitching and banking position of said fuselage, a switching valve connected to said motive means, a first valve means connected to said manually operable means and to said switching valve, a second valve means arranged to be operated by said manually operable means and connected to said switching valve, an altitude unit and an air speed unit forming a part of the trainer and respectively operable in response to changes in the assumed altitude and assumed air speed of said trainer, means operable in response to the operation of said air speed unit upon the reaching of a predetermined assumed air speed for rendering said manually operable control effective to raise one end of said fuselage by the operation of said second valve means, and means operable in response to the operation of said altitude unit upon the reaching of a predetermined assumed altitude for operating said switching valve to connect said first valve means to said motive means for rendering said manually operable control effective to universally pitch and bank said fuselage by the operation of said first valve means.

5. The combination of a grounded aviation trainer comprising a fuselage universally mounted with respect to a stationary base, manually operable means in the fuselage simulating the pitching and banking control means of a real plane, pneumatically operated motive means for changing the pitching and banking position of said fuselage, a switching valve connected to said motive means, a first valve means connected to said manually operable means-and to said switching valve, a second valve means arranged to be operated by said manually operable means and connected to said switching valve, an altitude unit and an air speed unit forming a part of the trainer and respectively operable in response to changes in the assumed altitude and assumed air speed of said trainer, means operable in response to the operation of said air speed unit upon the reaching of a predetermined assumed air speed for rendering said manually operable control effective to raise one end of said fuselage by the operation of said second valve means, means operable in response to the operation of said altitude unit upon the reaching of a pre-- determined assumed altitude for operating said switching valve to connect said first valve means to said motive means for rendering said manually operable control effective to universally pitch and bank said fuselage by the operation of said first valve means, and valve means forming a part of said trainer and connected to said switching valve for maintaining said fuselage in the level transverse position until both said predetermined assumed air speed and altitude are reached.

6. The combination of a grounded aviation trainer comprising a' fuselage unversally mounted with respect to a stationary base, manually operable means in the fuselage simulating the pitching and banking control means of a real plane, pneumatically operated motive means for changing the pitching and banking position of said fuselage, a switching valve connected to said motive means, a first valve means connected to said manually operable means and to said switching Valve, a second valve means arranged to be operated by said manually operable means and connected to said switching valve, an altitude unit and an air speed unit forming a part of the trainer and respectively operable in response to changes in the assumed altitude and assumed air speed of said trainer, means operable in response to the operation of said air speed unit upon the reaching of a predetermined assumed air speed for rendering said manually operable control effective to raise one end of said fuselage by the operation of said second valve means, means operable in response to the operation of said altitude unit upon the reaching of a predetermined assumed altitude for operating said switching valve to connect said first valve means to said motive means for rendering said manually operable control effective to universally pitch and bank said fuselage by the operation of said first valve means, valve means forming a part of said trainer and connected to said switching valve for maintaining said fuselage in the level transverse position until both said predetermined assumed air speed and altitude are reached, and means comprising said second valve means for maintaining said fuselage in a predetermined position about an axis transverse thereof until said predetermined assumed air speed is reached.

7. The combination of a grounded aviation trainer comprising a fuselage universally mounted with respect to a stationary base, manually operable means in the fuselage simulating the pitching and banking control means of a real plane, pneumatically operated motive means for changing the pitching and banking position of said fuselage, a switching valve connected to said motive means, a first valve means connected to said manually operable means and to said switching valve, a second valve means arranged to be operated by said manually operable means and connected to said switching valve, an altitude unit and an air speed unit forming a part of the trainer and respectively operable in response to changes in the assumed altitude and assumed air speed of said trainer, means operable in response to the operation of said air speed unit upon the reaching of a predetermined assumed air speed for rendering said manually operable control effective to raise one end of said fuselage by 'the operation of said second valve means, means operable in response to the operation of said altitude unit upon the reaching of a predetermined assumed altitude for operating said switching valve to connect said first valve means to said motive means for rendering said manually operable control effective to universally pitch and bank said fuselage by the operation of said first valve means, and

valve means operated by a displacement of said fuselage from the level transverse position and forming a part of said trainer and connected to said switching valve for maintaining said fuselage in the level transverse position until both said predetermined assumed air speed and altitude are reached.

8. The combination of a grounded aviation trainer comprising a fuselage universally mounted with respect to a stationary base, manually operable means in the fuselage simulating the pitching and banking control means of a real plane, pneumatically operated motive means for changing the pitching and banking position of said fuselage, a switching valve connected to said motive means, a first valve means connected to said manually operable means and to said switching valve, a second valve means arranged to be operated by said manually operable means and connected to said switching valve, an altitude unit and an air speed unit forming a part of the trainer and respectively operable in response to 21 changes in the. assumed altitude and assumed air speed of said trainer, means operable in response to the operation of said air speed unit upon the reaching of a predetermined assumed air speed for rendering said manually operable control effective to raise one end of said fuselage by the operation of said second valve means, means operable in response to the operation of said altitude unit upon the reaching of a predetermined assumed altitude for operating said switching valve to connect said first valve means to said motive means for rendering said manually operable control effective to universally pitch and bank said fuselage by the operation of said first valve means, valve means operated by a displacement of said fuselage from the level transverse position and connected to said switching valve for maintaining said fuselage in the level transverse position until both said predetermined as- 22 sumed air speed and altitude are reached, and means for operating said second valve means upon a displacement of said fuselage from a predetermined position about an axis transverse thereof to return said fuselage to the predetermined position about the transverse axis until said predetermined assumed air speed is reached.

RAYMOND H. LEWIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,947,962 Alfaro Feb. 20, 1934 2,063,231 Custer Dec. 8, 1936 2,099,857 Link Nov. 23, 1937 2,358,016 Link Sept. 12, 1944 

